Why didn't anybody tell me about Redis hash slots?

How much of the tools you use every day stays unnoticed...

I'm confused how you find the data again in this cache? It seems like you're randomly salting your cache keys, so I don't understand how subsequent requests find cached data.

Because you inherited it from someone who built it before that was a thing, and discovered it when you went serverless.

How'd I guess on the article itself?